Security in Wireless Ad Hoc Networks

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Security in Wireless Ad Hoc Networks
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Outline

• wireless ad hoc networks
• security challenges
• research directions
• two selected topics
• rational exchange
• incentives for cooperation

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Traditional wireless networks

• infrastructure
• base stations
• high speed backbone
• on-line servers
• network operators
• operate and maintain the system
• determine policies
• single-hop wireless communication

high speed backbone
on-line server
base station
mobile station
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Wireless ad hoc networks

• no infrastructure
• no base stations
• no backbone
• no servers (? P2P)
• no network operators
• self-organization
• self-configuration
• self-healing
• multi-hop wireless communication

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Applications of ad hoc networking technology

• battlefield
• rescue operations
• sensor networks
• spontaneous networks of personal devices
• e.g., conferences, meetings
• car networks
• pervasive computing
• connecting embedded computers
• e.g., connecting personal gadgets or household
  devices

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Hybrid networks (multi-hop cellular)

• advantages
• fewer base stations / larger coverage
• reduced total energy consumption of mobile
  stations
• reduced interference
• disadvantages
• synchronization?
• routing?
• QoS?

high speed backbone
on-line server
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Security challenges

• well-known security problems (authentication,
  session key establishment, ) must be solved
  under new assumptions
• set of assumptions depends on the envisaged
  application of the network, but usually
• no central authority can be assumed
• no access to on-line servers can be assumed
• network may be very dynamic (mobility, link
  failures, broken routes, )
• network lifetime may be short (transient
  associations)
• capacity of nodes may be limited (energy
  constraints, peanut CPU, small memory, limited
  communication in space and in time)
• nodes can be captured and compromised (no tamper
  resistance)
• new security problems specific to ad hoc networks
• selfishness, non-cooperative behavior
• new forms of DoS attacks (e.g., battery
  exhaustion)

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Current research directions

• decentralized public-key management schemes
• using threshold cryptography
• PGP-like approach
• exploiting mobility and secure side channels
• secure ad hoc routing
• various schemes for authenticating routing
  information that is distributed or exchanged
  among the nodes
• incentives for cooperation
• micro-payment based schemes
• reputation based schemes
• low cost cryptographic primitives (algorithms and
  protocols)
• anonymity, intrusion detection,
• researched in CrySyS in cooperation with EPFL
  and RSA Labs